Mince half the chick peas with a food processor. Heat 2 tbsp of olive oil in a pan with the garlic. When the garlic becomes brown, take it out of the pan with a spoon. Add to the pan the creamed chickpeas and the remaining chickpeas with chopped rosemary, salt and pepper. If the sauce is too thick, add some tbsp of the water used to cook the pasta. Cook the penne pasta, drain it and pour it into the pan with the sauce.